Oil additive and process for its preparation



United s a Patent 011. ADDITIVE AND PROCESS FOR ITS PREPARATION ThaddeusW. Culmer, R0binson, 11]., assignor to Hall Stewart No Drawing.Application September 17,1956

Serial N0. 610,396

7 Claims. (Cl. 260-504) I have discovered that alkaline earth metalalkylaryl sulfonates, and particularly alkaline earth metal petroleum ormahogany sulfonates, may be prepared and loaded with extremely highalkaline reserve in essentially a single operation. In this method, analkali metal petroleum sulfonate, otherwise known as a mahoganysulfonate, is heated with an aqueous solution of an alkaline earth metalhalide and an aqueous solution of either an alkali metal carbonate or analkali metal borate to simultaneously form the alkaline earth metalpetroleum sulfonate and load it with increased alkalinity. In thismethod, the

alkaline earth metal halide functions to provide the alkaline earthcontent of the sulfonate and the alkali metal salt, specifically thecarbonate or the borate, is used to provide the alkaline reserve-bearingcompound. The reaction between these reagents and the alkali metalsulfonate forms a connecting bridge of alkaline reserve radicals betweenthe alkaline earth sulfonate groups that are formed. I

' In preparing the oil additive, the alkali metal sulfonate, such astheordinary sodium mahogany sulfonate of com merce, is mixed preferablysimultaneously with two separate portions of an aqueous solution of analkaline earth metal halide, such as the halides of calcium, mang'anese,strontium, or barium, and an aqueous solution of either an alkali metalcarbonate or. an alkali metal borate. These twosolutionsare preferablyadded while the alkali metal petroleum sulfonate is maintained at anelevated temperature, preferably between about 180-210 F. The resultingmixture is then heated at a temperature above about 200 F. untilsubstantially all of the water has been driven off. When this procedureis followed, the resulting product or complex has up to three times ormore as much alkaline earth metal content as that of a neutral alkalineearth metal mahogany sulfonate. This value is expressed as having aloading value of 3-1, being three times that of the neutral sulfonate.

. A suitable alkaline earth metal halide is calcium chloride because ofits availability, inexpensiveness, and gen: erally satisfactory results.The aqueous solution of the alkaline earth metal halide and the aqueoussolution of either alkali metal carbonate or borate are added preferablysimultaneously in separate batches to the alkali metal petroleumsulfonate, preferably diluted with a neutral oil while agitating thesulfonate and while the sul- 5 fonate and oil mixture is at atemperature between about 180-210 F. After the addition has beencompleted, the heat is continued at a temperature that is above about200 F. until substantially all of the water has been driven off. Theheating temperature is preferably above 0 about 240 F. up to a maximumof about 350400 F. The amounts of alkaline earth metal halide and alkalimetal carbonate or borate used to react with the sodium sulfonate'ispreferably from 2-5 times the amount of the sulfonate on an equivalentweight basis. The mechanics of the various reactions involved arebelieved to be as follows with calcium chloride being used as an exampleof the alkaline earth metal halide, sodium carbonate as an example ofthe alkali metal carbonate, and sodium borate or borax as the alkalimetal borate, and the sodium mahogany sulfonate being expressed as NaOSOR: If an excess of CaCl is added to Na CO in solution, momentarily anintermediate com, pound is apparently formed before the resolution tothe end product CaCO -for instance: I

2CaCl +Na CO =CaCl CaCO +2NaCl structurally illustrated, this is asfollows:

C l-Ca This in turn appears to react with sodium sulfonate in thismanner:

CaCl CaCO +2NaOSO R=Ca(OSO R) CaCO '+2NaCl The structural formula isbelieved to be as follows:

The metal ratio is 2 to 1 and one mol of CaCO as' alkaline reserve .isavailable. However, for a safety factor in heavy duty oils, it ispreferred to use a 3 to 2 mol ratio:

On reaction with 2 mols of sodium sulfonate, the following appears totake place:

CaCl 2CaCO +2NaOSO R=CaOSO R2CaCO -l-2NaCl The structure of thiscompound is as follow: 5

be obvious that higher metal ratios may be secured by increasing theCaCl and Na CO quantities, limited only by the stability of thecarbonate-calcium chain. Thus it is apparent that when the metal ratiois to be increased, a molar excess of the alkaline earth metal halide(A.E.M.H.) should be maintained over the other two ingredients; namely,the alkali metal carbonate or borate .(AMC-B) and the alkali metalpetroleum sulfonate (AMPS). Expressed as a formula where N equals themolar proportions, N similarly indicates as N the metal reserve, thus:

N(AEMH) (N-l) (AMC-B) +(N-1) (AMPS) =N:1 Metal Reserve Ratio.

Example 1 1428 pounds of sodium sulfonate of about 3.5%

sodium content are blended with 1428 pounds of a lubricating oil stocksuch as l00@100 neutral in a kettle of suitable size equipped with meansof heating and stirring. The mixture is then heated.

When the temperautre of the agitated mass has reached 180-190 F., 333pounds of anhydrous CaCl dissolved in 1,000 pounds of water, and 212pounds of anhydrous Na CO dissolved in 1,000 pounds of water are addedsimultaneously and at the same rate, taking care that the solutions donot come in contact before entering the oil sulfonate mixture, and thatthey enter the oil as near the middle of the vortex of the agitation aspossible. As soon as both solutions are in the mix, CO is introducednear the bottom of the kettle and allowed to bubble slowly through themix throughout the operation. About pounds is sufficient for a batch ofthis size, and serves tovmainta'in the balance of CO in the carbonateduring processing. Although the use of CO is .preferre.d, lit.is notabsolutely necessary.

Stirring and heating are continued until thetemperature has reached 380F., at which .point the water is substantially removed. The product isthen filtered.

The theoretical Ca content of Ca(SO R)2CaCO in a l to l dilution withmineral oil is 3.93%. Repeated batches made by the method describedabove have shown a Ca content of around 4% It will be obvious to 'thoseskilled in the art that the carbonate-calcium chain can be lengthened togive yet greater calcium content, and that many anions other than thecarbonate may be employed. These anions, however, to be of practicalbenefit, must be polybasic and weak enough that their presence in theoil in the free state will not destroy the basicity of the calciumcation.

A good example of the latter class is the alkali metal borate such asborax.

Example 2 1428 pounds of sodium sulfonate (Na content approximately3.5%) and 1428 pounds of the above neutral lubricating stock are blendedwith heating and stirring in a blending kettle. At ISO- F. an aqueoussolution of 763 pounds borax in sufiicient water to effect completesolution and an aqueous solution of 333 pounds anhydrous CaCl in 1,000pounds of water are added simultaneously and separately in the samemanner as in Example 1 with the exception that no CO is employed.Heating and stirring are continued to expel water exactly as in Example1 and the resultant product is filtered.

This product has the formula Ca(SO R) 2CaB O- and is a bright viscousdark-colored oil-soluble compound.

On analysis this compound showed 3.79% Ca, 2.65% B, and had a sulfatedash of 21.35%.

Theoretical: 3.70 Ca 2.65 B.

The structural formula is believed to be as follows:

' Cat-O- In the foregoing, it is readily seen that an important featureof the invention is the conversion of sodium to calcium sulfonate andthe creation of alkaline reserve in the same operation without the aidof alkaline earth oxides or hydroxides.

The oxidation inhibitor thathas heretofore been added as a separateingredient maybe introduced .byincorporating a dithiophosphate in thesulfonate molecule itself.

Example 3 V 1428 pounds of sodium sulfonate (-Na content about 3.5% and1428 pounds neutralllubricatin'g stock were blended as in the otherexamples. 55S pounds anhydrous CaCl were dissolved in 1,000 poundswater. 222.3 pounds'P S were added slowly to a Solution off159 poundsanhydrous Na CO in 75 0pounds water at boiling temperature. A.vigo;rousreaction ensued, with a'result ant dark brownish green solution. 265pounds anhydrous Na CO were dissolved in 7 50 pound's water.

At 1:80190 F., the CaCl and NagCO solutions were added simultaneously to'the agitating oil vsulfonate mass, and immediately after, the P SNa5CO3 solution was added as quickly as possible, the speed being gov=erned by the foaming of the mass, which makes it necessary to add thesolution in small portions.

As before, the mass is heated with constant agitation to 380 400 F. toremove the water, then filtered.

The resultant product was a bright, dark-colored oilsoluble productwhich gave the following analysis:

Ca 5.7% P 2.315%

The detailed combination of the Ca is:

1.5% is thiophosphate 1.28% is neutral sulfonate 2.92% is alkalinereserve Due to the fact that the principal reactions of converting thesodium mahogany sulfonate to the alkaline earth metal sulfonate andloading it with alkaline reserve takes place in a simple reaction, itappears evident that the method of this invention lends itself readilyto the continuous production of the alkaline loaded sulfonates.

The additives of this invention may be added to any of the ordinarypetroleum lubricating oils by primarily heating and stirring the mixtureof oil and additive until the additive is dissolved. In general, theamount of additive employed may be any amount up to about 20% by weightof the oil. A satisfactory amount has been found to be about 5%. Allpercentages expressed herein are by weight.

Having described my invention as related to the embodiments set outherein, it is my intention that the invention be not limited by any ofthe details of description unless otherwise specified, but rather beconstrued broadly within its spirit and scope as set out in theaccompanying claims.

I claim:

1. A novel method of making an additive for a lubricating oil whichcomprises: (a) concurrently introducing into a quantity of an alkalimetal petroleum sulfonate two separate salt solutions, the first of saidsalt solutions consisting of an aqueous solution of an alkaline earthmetal halide and the second of said salt solutions consisting of anaqueous solution of an alkali metal salt selected from the groupconsisting of an alkali metal carbonate and an alkali metal borate, (b)admixing said salt solutions with said sulfonate, (c) the molar ratio ofthe said alkaline earth metal halide to the member selected from thegroup consisting of alkali metal carbonate and alkali metal borate being(N-l-l): N, where N is the number of mols of the alkali metal salt, (d)heating said admixture of materials sufliciently to maintain atemperature above about 200 F. and for a period of time suflicientlylong to drive ofi? all the water, and (e) recovering the resultingproduct.

2. The method according to claim 1, wherein the temperature of thealkali metal sulfonate is maintained between about 180 and 200 F. whilesaid two solutions are being added.

3. The method according to claim 1 wherein the alkali metal carbonate issodium carbonate.

4. The method according to claim 1 wherein the alkali metal borate issodium borate.

5. The method according to claim 1 wherein said admixture is heated to atemperature between 200 F. and 400 F.

6. The method according to claim 1 wherein the alkali metal sulfonate isdiluted with a neutral oil prior to admixing with said solutions.

7. The oil additive prepared by the method of claim 1.

References Cited in the file of this patent UNITED STATES PATENTS2,767,209 Assetf et al. Oct. 16, 1956 2,794,829 Waarden et al. June 4,1957 FOREIGN PATENTS 721,886 Great Britain Jan. 12, 1955 202,606Australia Apr. 28, 1955

1. A NOVEL METHOD OF MAKING AN ADDITIVE FOR A LUBRICATING OIL WHICHCOMPRISES: (A) CONCURRENTLY INTRODUCING INTO A QUANTITY OF AN ALKALIMETAL PETROLEUM SULFONATE TWO SEPARATE SALT SOLUTIONS, THE FIRST OF SAIDSALT SOLUTION CONSISTING OF AN AQUEOUS SOLUTION OF AN ALKALINE EARTHMETAL HALIDE AND THE SECOND OF SAID SALT SOLUTIONS CONSISTING OF ANAQUEOUS SOLUTION OF AN ALKALI METAL SALT SELECTED FROM THE GROUPCONSISTING OF AN ALKALI METAL CARBONATE AND AN ALKALI METAL BORATE, (B)ADMIXING SAID SALT SOLUTIONS WITH SAID SULFONATE, (C) THE MOLAR RATIO OFTHE SAID ALKALINE EARTH METAL HALIDE TO THE MEMBER SELECTED FROM THEGROUP CONSISTING OF ALKAKLI METAL CARBONATE AND ALKALI METAL BORATEBEING (N+1): N, WHERE N IS THE NUMBER OF MOLS OF THE ALKALI METAL SALT,(D) HEATING SAID ADMIXTURE OF MATERIALS SUFFICIENTLY TO MAINTAIN ATEMPERATURE ABOVE ABOUT 200* F. AND FOR A PERIOD OF TIME SUFFICIENTLYLONG TO DRIVE OFF ALLTHE WATER, AND (E) RECOVERING THE RESULTINGPRODUCT.